Question about buying Carter BBD for my 318 (unless I should look at something else)

I'm going to try this:

https://www.delphiautoparts.com/resource-center/article/how-to-test-the-alcohol-content-of-gasoline
Based on some web searching I've just done, I'm reading conflicting info about which gasoline brands and which octane has or doesn't have ethanol here in Ontario.

I was assuming any gas I buy anywhere, regardless of octane, has 10% enthanol. Maybe not?